Practical considerations for the use of a Howland current source for neuro-stimulation

We analyze the Howland current source circuit topology in detail with regards to non-ideal circuit component properties. This circuit is one of the few which can be built with a small number of discrete components, offers very good performance due to the use of an operational amplifier, and supplies true symmetric bi-directional currents, and is hence well suited for use in the multi-channel electrical stimulation of nerve fibers and neurons.